Headquarters of the French Internal Security (DGSI), Levallois-Perret, France. July 13, 2018. NICOLAS MESSYASZ/SIPA / SIPA

French authorities have arrested three people on suspicion of spying for Russia and acting to promote its war propaganda, as part of a probe into a French-Russian association, prosecutors said on Tuesday, November 25.

The arrests come as fears of Russian interference across Europe are at a high, with Western capitals pointing the finger at Moscow's spy services while the Kremlin's military campaign in Ukraine drags on.

One of those detained, a 40-year-old Russian man, was seen on video surveillance footage in September putting up pro-Russian posters on the Arc de Triomphe in Paris, the city's prosecutors' office said. The man then reported by telephone to the head of the association, SOS Donbass, a woman also aged 40, who was suspected by French counter-espionage officials of trying to get economic information from French company executives.

The woman, who was born in Russia, had been on the radar of France's domestic intelligence service, the General Directorate for Internal Security (DGSI), since at least the beginning of the year.